Well, it all depends whether there is a substantial amount of the active ingredient capable of inhibiting the reproductive process of the HIV virus. I would say it's plausible for a herbal medicine has the potential to destroy the HIV virus, but currently no significant results are being published.

Anyway, isn't it a lot easier to just synthesize the freaking compound in the lab to inhibit the HIV virus compared to finding some ancient herb that contains a similar compound? You get to play around with the structure of the compound to make it even more effective!

Welcome to science. You're gonna like it here - Phil Plait

Have you ever tried taking a comfort blanket away from a small child? - DLJ